OFFSET
1,2
COMMENTS
The array is always extended by its antidiagonals with the smallest term not yet present that doesn't lead to a contradiction. The sequence is thus the lexicographically earliest of its kind.
FORMULA
a(n*(n-1)/2 + 1) = a(n). - Rémy Sigrist, May 21 2019
EXAMPLE
Array:
1 2 3 3 4 5 3 6 7 8 4 ...
3 4 6 9 13 18 24 31 39 48 58 ...
5 7 10 14 19 25 32 40 49 59 70 ...
8 11 15 20 26 33 41 50 60 71 83 ...
12 16 21 27 34 42 51 61 72 84 97 ...
17 22 28 35 43 52 62 73 85 98 112 ...
23 29 36 44 53 63 74 86 99 113 128 ...
30 37 45 54 64 75 87 100 114 129 145 ...
38 46 55 65 76 88 101 115 130 146 163 ...
47 56 66 77 89 102 116 131 147 164 182 ...
57 67 78 90 103 117 132 148 165 183 202 ...
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Eric Angelini, May 21 2019
STATUS
approved